So if they were brought by your father, that would be in the 1930's. Any idea of how old they were then, or where they came from. My guess is that they are
Aldabra Tortoises from the Aldabra Atoll in the Seychelles, or maybe from Zanzibar, where there is said to be a small population.
[btw, to add pictures, click on "Additional Options" when you are making a post]
David